3 files changed, 33 insertions, 9 deletions

diff --git a/gnu/packages/fabric-management.scm b/gnu/packages/fabric-management.scm
index 15fd751f045..d979d87f302 100644
--- a/gnu/packages/fabric-management.scm
+++ b/gnu/packages/fabric-management.scm
@@ -2,7 +2,7 @@
 ;;; Copyright © 2017 Dave Love <fx@gnu.org>
 ;;; Copyright © 2018, 2019 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2019 Ricardo Wurmus <rekado@elephly.net>
-;;; Copyright © 2019, 2023 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2019, 2023, 2026 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -226,15 +226,19 @@ testing InfiniBand networks.")
 
                            (string-append "--with-rdmacm="
                                           #$(this-package-input "rdma-core"))
-                           (string-append "--with-rocm="
-                                          #$(this-package-input "rocr-runtime")))
+
+                           #$@(if (this-package-input "rocr-runtime")
+                                  #~((string-append "--with-rocm="
+                                                    #$(this-package-input
+                                                       "rocr-runtime")))
+                                  #~()))
 
       ;; Be verbose so that compiler flags are displayed.
       #:make-flags #~'("V=1")))
     (native-inputs
      (list autoconf automake libtool pkg-config))
     (inputs
-     (list numactl rdma-core rocr-runtime))
+     (list numactl rdma-core))
     (synopsis "Optimized communication layer for message passing in HPC")
     (description
      "Unified Communication X (UCX) provides an optimized communication layer
@@ -250,3 +254,13 @@ memory mechanisms for efficient intra-node communication.")
     ;; and x86_64 as supported.
     (supported-systems '("x86_64-linux" "aarch64-linux" "powerpc64le-linux"
                          "riscv64-linux"))))
+
+;; Note: ROCm support is kept separate to avoid a significant increase in
+;; closure size: <https://codeberg.org/guix/guix/issues/7225>.
+(define-public ucx-rocm
+  (package/inherit ucx
+    (name "ucx-rocm")
+    (inputs (modify-inputs inputs
+              (append rocr-runtime)))
+    (synopsis "Optimized communication layer for message passing in HPC (with
+ROCm support)")))
diff --git a/gnu/packages/linux.scm b/gnu/packages/linux.scm
index 469a6f0c2a0..9ee8f2362b8 100644
--- a/gnu/packages/linux.scm
+++ b/gnu/packages/linux.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012-2021, 2021-2025 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012-2021, 2021-2026 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2013, 2014, 2015, 2016 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2012 Nikita Karetnikov <nikita@karetnikov.org>
 ;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019, 2020 Mark H Weaver <mhw@netris.org>
@@ -10460,7 +10460,6 @@ known as Slingshot.")
                   (cons package extra)
                   '()))))
        (append (list rdma-core libnl)
-               (if-supported rocr-runtime)
                (if-supported psm)
                (if-supported psm2)
                (if-supported libcxi curl json-c))))
@@ -10504,6 +10503,15 @@ applications deal with directly.  It works in conjunction with provider
 libraries, which are often integrated directly into libfabric.")
     (license (list license:bsd-2 license:gpl2)))) ;dual
 
+;; Note: ROCm support is kept separate to avoid a significant increase in
+;; closure size: <https://codeberg.org/guix/guix/issues/7225>.
+(define-public libfabric-rocm
+  (package/inherit libfabric
+    (name "libfabric-rocm")
+    (inputs (modify-inputs inputs
+              (append rocr-runtime)))
+    (synopsis "Open Fabric Interfaces (with ROCm support)")))
+
 (define-public libfabric-1                        ;needed by Open MPI 4.x
   (package
     (inherit libfabric)
diff --git a/gnu/packages/mpi.scm b/gnu/packages/mpi.scm
index bd891940e1d..5d975bc7532 100644
--- a/gnu/packages/mpi.scm
+++ b/gnu/packages/mpi.scm
@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2014, 2015, 2018, 2019 Eric Bavier <bavier@member.fsf.org>
-;;; Copyright © 2014-2025 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014-2026 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2014 Ian Denhardt <ian@zenhack.net>
 ;;; Copyright © 2016 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2017 Dave Love <fx@gnu.org>
@@ -432,7 +432,7 @@ software vendors, application developers and computer science researchers.")
   (package/inherit openmpi-5
     (name "openmpi-rocm")
     (arguments
-     (substitute-keyword-arguments (package-arguments openmpi-5)
+     (substitute-keyword-arguments arguments
        ((#:configure-flags flags '())
         #~(cons* (string-append "--with-rocm="
                                 #$(this-package-input "rocm-hip-runtime"))
@@ -440,7 +440,9 @@ software vendors, application developers and computer science researchers.")
     (inputs (modify-inputs (package-inputs openmpi-5)
               ;; XXX: This might break openmpi-5 for architectures where ROCm
               ;; is not supported.
-              (append rocm-hip-runtime)))
+              (append rocm-hip-runtime)
+              (replace "ucx" ucx-rocm)
+              (replace "libfabric" libfabric-rocm)))
     (synopsis "MPI-3 implementation (with ROCm support)")))
 
 (define-public openmpi-c++